Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Royalty income	$ 274,648	$ 270,178	$ 259,246
License fees	0	10,000	0
Diagnostic service revenue	13,789	0	0
Other revenue	24,375	0	0
Total revenues	312,812	280,178	259,246
Costs and expenses:
Cost of revenue	629,191	15,441
Research and development	10,593,869	6,664,906	3,947,589
Selling and marketing	6,443,578	2,734,903	1,530,160
General and administrative	7,919,826	5,810,087	5,472,038
Total operating expenses	25,586,464	15,225,337	10,949,787
Loss from operations	(25,273,652)	(14,945,159)	(10,690,541)
Interest income	57,261	12,239	3,663
Interest expense	(1,525,482)	(843,259)	(17,005)
Other (income) expense, net	(2,800)	24,845	(22,941)
Gain (loss) from change in fair value of derivative instruments—warrants	(726,421)	1,425,850	(1,084,114)
Net loss and comprehensive loss	(27,471,094)	(14,325,484)	(11,810,938)
Preferred stock dividend	(24,240)	(23,015)	(29,840)
Net loss and comprehensive loss attributable to common stockholders	$ (27,495,334)	$ (14,348,499)	$ (11,840,778)
Net loss per common share - basic (in dollars per share)	$ (1.05)	$ (0.76)	$ (0.70)
Net loss per common share - diluted (in dollars per share)	$ (1.21)	$ (0.88)	$ (0.70)
Weighted-average shares outstanding - basic (in shares)	26,201,713	18,904,280	16,978,212
Weighted-average shares outstanding - diluted (in shares)	26,452,165	19,071,112	16,978,212